In a known device of this type (DE-GM No. 77 23 157), the end of a lever away from a drive is provided with a slotted head which engages a prong that is directly or indirectly connected with a cutting part that moves back and forth. This drive connection has been customary for a long time in several variants, but has several disadvantages. The design of the lever head and of the prong requires relatively high precision, to avoid rattling noises and their associated wear. On the other hand, frictional energy is consumed through the relative motion between the head and the prong, and the springy engagement between these two components can lead to amplitude losses of the moving cutting part. Finally, because of relatively unfavorable bearing and driving conditions, the moved cutting part, or the slide which supports it, tend to produce staggering motions and to the running noises consequent therefrom.